Optimization and Criterions of Collaborative Sensing under Transmission Power Constraint

In cognitive networks, cognitive (unlicensed) users need to continuously monitor spectrum to detect the presence of primary (licensed) users. In this paper, collaborative spectrum sensing scheme is exploited as the masterstroke., furthermore, cognitive users transmission powers are constrained, and the relative positions among the two cognitive users and the primary user in the three-dimensional space are randomly distributed, which are very closer to the actual working environment, Based on these conditions, a new model to optimize the performance of collaborative sensing is proposed. The feasibility of the model is well explained and supported by extensive simulations. The study results indicate that under the invariability of the operating mode, path loss, channel gain, and the transmission signal power of primary user, collaborative sensing performance is affected by the relative position changes between users and cognitive users, and transmission power change, but optimization can be achieved under certain conditions. The criterions proposed in the paper not only made cooperative spectrum sensing performance be improved, but also considerable narrowed the scope of cooperative sensing search.